Give reasons for the following
(a) `CO_(2)` has no dipole moment but `SO_(2)` and `H_(2)O` have considerable dipole moments
(b) Carbon has two unpaired electrons in the outermost orbit, but it is tetravalent in organic compound
(c ) `CaF_(2)` is more ionic than `CaI_(2)`
(d )Sigma bonds are stronger than pi bonds
(e) `C_(2)H_(4)` is planar while `C_(2)H_(2` is linear
(f) `H_(2)O` is more polar than `H_(2)S`
(g) Ionic compounds do not canduct electricity in solid state, but they conduct electricity in solution or in molten state .

Explanation

(i) `CO_(2)` is sp htybridised linear having `mu=0`
(ii) `H_(2)O` is `sp^(3)` hybridised angular or bent in shape having `mu ne 0`
(iii) `SO_(2)` is `sp^(2)` hybridised angular or bent in shape having `mu ne 0`
(b) Valence electrnic configuration of `C` atom in ground sate `=2s^(2) 2P^(2)`
Valence electronic configuration of `C-`atom in excited sate `=2s^(1)2p_(x)^(1) 2p_(y)^(1)2p_(z)^(1)` (4unpaired `e^(-'s)`
Hence `C` is tetravalent Due to excitation of `e^(-)'s` from 2s orbital to 2p orbitalresults in its tetravalence
(c ) Same explanation as in solution of Question 9 (f) (Apply Fajans' rule)
(d) `sigma` bonds are formed as a result of end to-end overlapping of orbitals on the nodal plane Hence, `e^(-')s` most of the time lie on nuclear axis which give sterenght to the 'sigma' bond Whereas in `pi` bonds `e^(-')` s lie either above or below the nuclear plane and are far from nucleus Hence 'pi' bond is weaker than 'sigma' bond
(e) In `C_(2)H_(4)(H_(2)C=CH_(2))`, C-atom is `sp^(2)` hybridised and its shape is planar, whereas in `C_(2)H_(2)(HC-=CH)` C-atom is sp hybridised and its shape is linear
(f) Due to high `EN` of O-atom `O-H` bond in `H_(2)O` is highly polar whereas in `H_(2)S,S-H` bond is not polarised to that extent due to low `EN` difference
(g) In solid state ions of ionic compounds are held together very strongly by electrosatic attration In molteh or aqueous sate ions become free and hence conduct electricity
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